Optical heating of metallic nanoparticles for fast injection of nanoscale sensor into living cells

Optical heating of metallic nanoparticles is of great significance to biological and biomedical applications, such as gene/molecule delivery and intracellular microenvironment measurement. In this study, we propose to employ optical heating of metallic nanoparticles to achieve fast injection of single nanoscale sensor into living cells. The nanoscale sensor consists of polystyrene bead, which is embedded with iron oxide nanoparticles and dyed with Rhodamine B for temperature sensitivity. A fluid of the nanoscale sensors was incubated into cell culture medium for adhesion onto cell membrane. When irradiated by 1064 nm continuous-wave laser, the embedded iron oxide nanoparticles serve as heater due to their surface plasmonic properties. It contributes to fast injection of the nanoscale sensor into living cells. Our experiment results indicate that under laser irradiation with power of 7 mW the nanoscale sensor is successfully injected into living cells in 8 sec. Furthermore, with an increase in power from 7 to 35 mW the injection time decreases from 8 to 1 sec. In addition, our experimental results indicate that after injecting the nanoscale sensor into living cell the injected cells have a survival rate of 100%.